"core portion" is a correct and usable phrase in written English.
You could use it to describe the most important or essential part of something, such as in this example: "The core portion of the report focused on the effectiveness of the new product launch."
The core portion of the country's consumer price index, which excludes volatile items like gasoline and mortgage interest, was 1.6percentt in November, compared with 1.8percentt in October.
The council rejected the core portion of the measure, under which a newly created agency, acting on the recommendations of copyright owners, would have been able to order Internet service providers to shut down the accounts of copyright cheats who ignored two warnings to stop.
The core portion of psana is written largely in C++, but psana supports both C++ and Python as user interfaces.
At high temperature, the PMMA core portion was totally decomposed to gaseous products without remaining residual material [13].
This may occur if the core portion of the nanofiber was not at the center, but on the edge of the PMMA/PAN nanofibers during electrospinning.
For the core portion of the explanation, in the action video the speaker used gestures that portrayed the action of each part.
For instance, Linus Torvalds, the creator of Linux, screens patches for the core portions of that operating system.
All coaxial nozzle electrospinning samples exhibit the core-shell morphology, which the core portions were uniformed along the center of the nanofibers.
We controlled the distance between each flow microchannel (hollow core portions and interspace of the microfibers) to be within 150 μm by using microfibers with a gel thickness of approximately 50 μm.
Copper(I) complexes with {Cu μ2-S N}4 and {Cu μ3-S N}12 core portions of butterfly-shaped or double wheel architectures have been isolated in the reaction of Cu(I) with the Schiff base ligand C6H4(CHNC6H4S)2, "iso-abt", under different conditions.
These rites may change slightly across different traditions, but the core portions remain the same.
